With the development of industry and advancement of society, an increasing attention has been paid to atmospheric pollution. Before the twelfth five years, China only emphasizes on controlling the emission of SO2 but ignores the control of emission of NOx in the aspect of cleaning up smokes from coal-fired power plant. Datas show that NOx not only have biological toxicity and do harm to the health of humankind, but also gives rise to a serial of environmental problems such as acidic rains, photochemical smog and ozone layer depletion. It has been reported that the emitting amount of NOx in China reaches 20 million tons in 2008. If the trend still remains uncontrolled, the emitting amount of NOx will reach 30 million tons in 2020 and will become the first largest acidic gas pollutant. Just because of that, during the twelfth five years, it has become one of major national decisions of China to comprehensively promote the denitration in coal-fired power plant. As far as the present phase, main denitration techniques at home and abroad include two categories: selective catalytic reduction technique (SCR) and selective non-catalytic reduction technique (SNCR), in which SCR denitration technique is to selectively reduce NOx by means of NH3 with the presence of catalyst. As compared to the SNCR technique that only uses NH3 as reductant, the SCR denitration technique not only has a higher efficiency of denitration, but also has a lower consumption amount and escaping ratio of NH3, hence, SCR technique is consider to be the most economic and effective technique for denitration.
There are three installation modes for SCR reactor, which are called high-dust smoke SCR (HD-SCR), low-dust smoke SCR (LD-SCR) and tail-end SCR(TE-SCR), respectively. The selected catalysts are generally commercial catalyst V2O5-WO3/TiO2 or V2O5-MoO3/TiO2. In the former two installation modes, the SCR reactor is required to be installed before desulfurizing tower, the disadvantage of which lies in that SO2 at high concentration in smoke can cause poisoning of catalyst and bring loss of catalyst's activity; whereas, when TE-SCR technique is adopted, SCR reactor is installed behind desulfurizing tower, which can largely reducing the influence of SO2 on catalyst's performance. However, the biggest problem that this kind of installation mode faces lies in that active temperature window of current commercial vanadium-based catalyst ranges from 300 to 400° C., whereas, temperature of smoke in outlet of desulfurizing tower is commonly at 80 to 150° C., which requires the heating of smoke before its entry into SCR reactor, resulting in the great increase in operating costs. Therefore, it has become a key technical obstacle for SCR denitration technique on how to produce a high efficient SCR catalyst at low temperature. SCR catalyst comprises such two parts as active components and carriers. As far as the catalyst for denitration, selection of carriers tends to be diversified. The carriers mainly include TiO2, zeolite, molecular sieve, Al2O3, active carbon and so on. These catalysts have their own advantages, but also have inevitable defects, e.g. TiO2 and Al2O3 don't have enough specific area; zeolite, molecular sieve and active carbon have smaller pore size etc. Consequently, it is vital to select appropriate carriers for catalyst for the purpose of increasing the selectivity of carriers. Active components of catalyst for denitration has tendencies to develop from single component to double components and even multiple components, not only includes common oxides such as W, V, etc, but also includes transition metal oxides such as Fe, Mn, Cu and Ce, etc. These active components can be applicable to diverse temperature ranges and can achieve the goals of elevating catalysts' denitration activities while broadening denitration temperature window by way of coordination of these active components between them. Therefore, it is significantly meaningful for the production of novel and high efficient catalyst for denitration at low temperature through designed combination of active components and carriers of catalyst.